KR19990046545A - coding transmitting-receiving apparatus and method - Google Patents

Abstract

The present invention provides a method and method for encrypting and transmitting a multimedia data using a PN code assigned to the client and a terminal ID of the client to double-encrypt the multimedia data before transmitting the multimedia data. It is about.

An apparatus for transmitting and receiving an encryption according to the present invention comprises a client for ordering multimedia data and a multimedia service center for providing a multimedia service, wherein the multimedia service center assigns the multimedia data to the client when the multimedia data is ordered from the client. A code and a terminal ID are encrypted and transmitted, and the client decrypts the encrypted data received from the multimedia service center using its own PN code and a terminal ID.

Description

Encryption transmitting-receiving apparatus and method

The present invention relates to an apparatus and method for encrypting transmission and reception. More specifically, when a multimedia data is ordered from a client, only a legitimate user is transmitted by double encrypting and transmitting multimedia data using a PN code assigned to the client and a terminal ID of the client. An apparatus for transmitting and receiving an encryption and a method for restoring corresponding data are provided.

Due to the rapid development of the Internet and the dissemination of computers, the distribution and sharing of multimedia data through a network has been rapidly performed. As a result, multimedia digital information such as text, image, sound, video, etc. It is possible to make a large amount of copies without the author's consent on the Internet, and after copying, it can be copied and distributed without the author's consent.

Therefore, in the case of a service provider that provides a multimedia service, it is necessary to prepare for the above-described problems. For this purpose, a digital watermarking technique is applied to insert a signature or a predetermined code of the author into the data itself. I'm trying to. However, in practice, a lot of time and development are required for the commercialization of digital watermarking technology.

Therefore, there is a need for a technique for preventing unauthorized copying of multimedia information using a network as described above.

Meanwhile, Code Division Multiple Access (hereinafter referred to as CDMA), which is currently common in mobile communication, was proposed by Qualcomm, Inc. in 1989, and the Telecommunication Industry Association. Standardized by Association (Interim Standard IS-95). In the CDMA scheme, a plurality of users may share the same frequency band, and a pseudo-noise code (hereinafter, referred to as a PN code) unique to a user communication channel is used to distinguish users. That is, the PN code is used to spread and transmit the transmission frequency band in a band of several tens or more times the voice data frequency band, and the receiving side demodulates the original signal using the same code as the PN code used at the time of transmission.

Spread-Spectrum communication method, which is the basis of CDMA technology, has the advantage of being strong in the interference of narrow-band signals, and solves the existing frequency band problem with PN code and Walsh function. Transmit multiple user codes on the same frequency.

The aforementioned spread spectrum communication method transmits information using a bandwidth wider than the theoretical bandwidth required for transmitting specific information. The efficiency of the frequency band is decreased, but the error efficiency (or signal to noise ratio) is improved. In addition, even if the intensity of the spread signal transmitted is very weak, the communication is possible and strong against the noise signal, so that even if many senders send a signal at the same time can transmit the signal to a specific receiver with a specific code (spreading code). That is, the capacity can be increased by the same channel can be used by multiple users at the same time. In the spread spectrum method, a direct sequence spread spectrum (DS-SS) method in which a signal source is modulated using a PN code to spread a band, and a frequency hopping spread that spreads a carrier frequency by a set of frequencies Frequency Hopping Spread Spectrum (FH-SS), a Time Hopping Spread Spectrum (TH-SS) and a chip that compresses a block of data and transmits intermittently within a frame of numerous time periods. chip) There is a spread spectrum technique, and a hybrid method using two of them is also widely used.

As described above, in the spread spectrum communication method, a signal such as perfect noise must be used as a spreading code as a spreading code, but a spreading code such as noise has to use a different code for each subscriber. Therefore, the IS-95 scheme is used to distinguish between the base station and the long code used for the reverse channel and the base station, which are orthogonal spreading codes used to distinguish each channel transmitted by the mobile station to the base station in the forward channel. There is a short code to do this.

1A and 1B exemplarily illustrate conversion and restoration states of an original signal using a PN code. As shown in Fig. 1A, when the receiving side receives the spreading signal generated by multiplying the original spreading code by the transmitting spreading code at the transmitting side and multiplies the spreading code identical to the spreading code used by the transmitting side, the original signal is restored to the original signal. You can see it.

However, as shown in FIG. 1B, when a spread signal received from a transmitter is multiplied by a wrong spread code that is not the same as the spreading code of the sender, the receiver is restored to a completely different signal from the original signal. Will receive.

In order for the spreading code that plays such a role to effectively spread spectrum, there must be no cross-correlation as shown in Equation 1 for each spreading code at any arbitrary time T.

PN codes that reflect the characteristics of the spread spectrum code as described above generally have the following characteristics: first, the repetition period should be long enough, and second, the number of 0s and 1s in one period should be similar. The third consecutive repetition of the number must be one-half of the total code, the second is 1/4, the third is 1/8, and so on. The association must be very small, the fifth smallest sequence fragment cannot be reproduced by the entire sequence fragment, and the sixth must be reproducible by an appropriate reproduction algorithm.

The present invention has been made in view of the above-described needs, and when the multimedia data ordered from the client, the multimedia data using the PN code assigned to the client and the terminal ID of the client is double encrypted and then transmitted, and the encrypted data is received. The purpose of the client is to provide an encrypted transmission and reception apparatus and method for restoring data using a PN code assigned to it and its terminal ID to reproduce the original signal so that only the right user can use the data.

1A and 1B exemplarily illustrate conversion and restoration states of an original signal using a PN code;

2 is a diagram showing the configuration of an apparatus for transmitting and receiving encryption according to an embodiment of the present invention;

3 is a diagram illustrating a configuration of a PN generator using a shift register.

4 is a flowchart illustrating a user registration and terminal ID grant process;

5 is a flowchart illustrating a data request and a data encryption process;

6 is a flowchart for explaining a data reproduction process.

*** Explanation of symbols for the main parts of the drawing ***

10.A / D converter, 20, 50.PN code generator,

30, 60. Terminal ID storage, 40, 70. Encoder,

80. D / A Converter

An apparatus for transmitting and receiving an encryption according to the present invention for achieving the above object comprises a client for ordering multimedia data and a multimedia service center for providing a multimedia service. It is encrypted by using the PN code and the terminal ID assigned to the client and transmitted, and the client is characterized by decrypting the encrypted data received from the multimedia service center using its own PN code and terminal ID. Furthermore, the multimedia service center includes a PN code generator for generating a PN code assigned to the client; A memory unit storing information of the client, a PN code assigned to the client, and a terminal ID; And an encoder for encrypting the data ordered from the client using the PN code provided from the PN code generator and the terminal ID provided from the memory unit, wherein the client generates a PN code assigned thereto. A PN code generator; A terminal ID storage unit having its terminal ID stored therein; And an encoder for decoding the encrypted data transmitted from the multimedia service center by using the PN code provided from the PN code generator and its terminal ID provided from the terminal ID storage unit.

On the other hand, the encrypted transmission and reception method of the present invention provides an encryption transmission and reception apparatus, comprising: a user registration and terminal ID granting process of registering a user's information for receiving a multimedia service and granting a terminal ID; A data request and data encryption process of encrypting and transmitting data using a corresponding PN code and a corresponding terminal ID when ordering multimedia data; And a data reproducing process of decrypting the received encrypted data using its own PN code and its own terminal ID. Further, the user registration and terminal ID granting process may include receiving user information from a user for receiving a multimedia service; Generating a PN code and a terminal ID not duplicated with another user based on the received user information; Storing the received user information, the generated PN code, and terminal ID in a corresponding memory unit; and transmitting the PN code and terminal ID to a subscriber of a terminal to which the terminal ID is assigned. The data request and data encryption process may include receiving user information of a user for receiving a multimedia service; Searching for a PN code and a terminal ID of the corresponding user based on the received user information; Encrypting data ordered by a client using the PN code; Encrypting the data using the retrieved terminal ID; And transmitting the encrypted data to a corresponding subscriber, and the data reproducing process includes: decrypting the encrypted data received from the multimedia service center using its own PN code; Decrypting the data using its terminal ID; And reproducing data restored to the original signal.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the encryption transmission and reception apparatus and method according to a preferred embodiment of the present invention.

2 is a diagram showing the configuration of an apparatus for transmitting and receiving encryption according to an embodiment of the present invention.

Prior to the description, in the present embodiment, a spread spectrum code is applied to an AOD (Audio On Demand) service that provides an audio signal such as voice or music. Considering that all multimedia data other than the AOD service is digitized, spread spectrum It is clear that the coded digital data distribution technology can be applied to all on-demand multimedia data services such as text, images and video.

As shown in FIG. 2, an apparatus for transmitting and receiving encryption according to an embodiment of the present invention includes a client that orders multimedia data and an AOD center that provides an audio signal ordered by the client. An analog-to-digital converter (10), a PN code generator (20), a terminal ID storage unit (30), and an encoder (40) are provided.

In the above configuration, the A / D converter 10 converts the sound file ordered by the client into a digital signal.

The PN code generator 20 generates a PN code assigned to the client who ordered the multimedia data. Here, the PN code generator 20 generates a PN code based on data provided from a PN code storage unit (not shown) in which a PN code assigned to a client ordering multimedia data is stored.

The terminal ID storage unit 30 stores a terminal ID assigned to the client who ordered the multimedia data.

The encoder 40 double encrypts (encodes) data using the PN code input from the PN code generator 20 and the terminal ID provided from the terminal ID storage unit 30.

Here, the PN code and the terminal ID are individually assigned to the service user, which is the same as the mobile subscriber is given a unique terminal.

That is, if there is a data order from the client, the AOD center encrypts the data so that other users cannot use the data, and encrypts the data using the PN code received from the PN code generator 20, and the terminal ID storage unit ( The data is encrypted once more using the terminal ID provided from 30).

As described above, the reason for performing encryption twice using the PN code and the terminal ID assigned to the client who ordered the multimedia data is to prevent an unauthorized user from easily restoring the data.

3 is a diagram exemplarily illustrating a configuration of a PN code generator using a shift register.

In general, a shift register is used to generate a code that reflects the characteristics of a spread spectrum code. There is a Modular Linear Feedback Shift Register (MLFSR) method. In the case of using SLFSR, the Characteristic Polynomial is used. In the case of MLFSR, the Reciprocal of Characteristic Polynomial is used. The latter case is the standard implementation of IS-95 and is commonly used.

The PN code generator shown in FIG. 3 is configured by using a 3-bit register. In general, the PN code is configured to have a different code sequence depending on an initial state.

Table 1 shows the values output using the PN code generator of FIG. 3 with the state of the initial register specified as [1,1,1], and Table 2 shows the state of the initial registers [1,1,0]. ] Is a table showing values output using the PN code generator of FIG. 3 in the state specified by]. As shown in Table 1 and Table 2, even if the initial state of the PN code generator differs by only one bit, the code strings generated are each [ 111010] and [011101] can be seen to be completely different.

n F1 F2 F3 Print One One One One 2 0 One One One 3 One 0 One One 4 0 One 0 One 5 0 0 One 0 6 One 0 0 One 7 One One 0 0

n F1 F2 F3 Print One One One 0 2 One One One 0 3 0 One One One 4 One 0 One One 5 0 One 0 One 6 0 0 One 0 7 One 0 0 One

The PN code generator that is actually applied to the present invention may be implemented as a 30-bit or 42-bit shift register, and in this case, a PN code that can be actually generated may generate 2 ³⁰ -1 different PN codes when the shift register is 30 bits. In the case of 42 bits, 2 ⁴² -1 different PN codes can be generated.

Meanwhile, the client includes a PN code generator 50, a terminal ID storage unit 60, an encoder 70, and a D / A converter (Digital to Analog Converter) 80.

In the above-described configuration, the PN code generator 50 generates a PN code assigned to the client itself, and is based on data provided from a PN code storage unit (not shown) in which the PN code allocated from the AOD center is stored. To generate the PN code.

The terminal ID storage unit 60 stores a terminal ID assigned to the terminal ID storage unit 60.

The encoder 70 decrypts the encrypted data received through the Internet using the PN code received from the PN code generator 50 and the terminal ID received from the terminal ID storage 60 into an original signal.

The D / A converter 80 converts the signal recovered by the encoder 70 into an analog signal.

4 to 6 are flowcharts illustrating an encryption transmission and reception method.

Hereinafter, an overall encryption transmission and reception process will be described with reference to FIGS. 2 and 4 to 6.

4 is a flowchart illustrating a user registration and terminal ID assignment process.

First, the user applies for a terminal to apply for the AOD service, the user must store his information in the AOD server in order to receive the service, at this time, the PN code generator 20 and the terminal ID provided in the AOD center Generators (not shown) generate PN codes and terminal IDs that do not overlap with other users. As described above, the PN code and the terminal ID generated by the PN code generator 20 and the terminal ID generator (not shown) are stored in the corresponding memory unit in association with the user information and then transmitted to the subscriber of the terminal assigned the terminal ID. . Here, the PN code is stored in the PN code storage unit (not shown), and the terminal ID is stored in the terminal ID storage unit 30. As such, the client, which has received its PN code and terminal ID from the AOD center, stores the received PN code in the PN code storage unit (not shown), and stores the terminal ID in the terminal ID storage unit 60.

As described above, since there is no duplicate PN code and terminal ID, only the corresponding terminal can decrypt the requested data.

5 is a flowchart illustrating a data request and a data encryption process. As shown in FIG. 6, when a user transmits his or her information to receive an audio file from an AOD center, the AOD center uses a terminal ID storage unit 30 and a PN code storage unit using the user information received from the client. Inquire the PN code and the terminal ID of the corresponding user. As such, when the PN code and the terminal ID of the user who requested the data service are retrieved, the AOD center generates the retrieved PN code in the PN code generator 20 and then uses the PN code generated in the PN code generator 20. Multiplies the data requested by the server and encrypts it once, multiplies the retrieved terminal ID by the data twice, and sends the encrypted data to the user.

6 is a flowchart for explaining a data reproduction process. As shown in Fig. 7, the legitimate user should play back the original signal upon receiving the corresponding data from the AOD center. The terminal ID is used to decode the original signal. That is, the received signal is restored by multiplying the received encrypted data by the PN code received from the PN code generator 50 and multiplying the terminal ID stored in the terminal ID storage unit 60 with the data to restore the original signal. . Here, the PN code and the terminal ID used when encrypting the data at the AOD center and decrypting the data at the client should be the same. If not, data such as noise will be recovered.

On the other hand, the audio player and the player are configured in the same system, and since the terminal ID value is different in the terminal of another person, not the own terminal, data such as noise will be restored.

The encryption transmission and reception apparatus and method of the present invention are not limited to the above-described embodiments, and may be variously modified and implemented within the range permitted by the technical idea of the present invention.

According to the encryption transmission and reception apparatus and method of the present invention as described above, when the multimedia data ordered from the client, the multimedia data using the PN code assigned to the client and the terminal ID of the client and then double-encrypted and transmitted, encrypted data The client receives the PN code and its terminal ID to restore the data to reproduce the original signal, so that only the right user can use the data.

In addition, for this reason there is an effect that can prevent the duplication and distribution of the user billing system and multimedia data.

Claims (7)

In the transmission and reception device comprising a client for ordering multimedia data and a multimedia service center for providing a multimedia service, When the multimedia service center orders multimedia data from the client, the multimedia service center encrypts the multimedia data using the PN code and the terminal ID assigned to the client, and the client transmits the encrypted data received from the multimedia service center to its own PN. Encrypting transceiver device, characterized in that for decrypting using a code and a terminal ID. The method of claim 1, wherein the multimedia service center A PN code generator for generating a PN code assigned to the client; A memory unit storing information of the client, a PN code assigned to the client, and a terminal ID; And And an encoder for encrypting data ordered from the client using a PN code provided from the PN code generator and a terminal ID provided from the memory unit. The method of claim 1, wherein the client is A PN code generator for generating a PN code assigned to it; A terminal ID storage unit having its terminal ID stored therein; And And an encoder for decrypting the encrypted data transmitted from the multimedia service center by using the PN code provided from the PN code generator and its own terminal ID provided from the terminal ID storage unit. . In the encryption transceiver, A user registration and terminal ID granting process of registering a user's information for providing a multimedia service and granting a terminal ID; A data request and data encryption process of encrypting and transmitting data using a corresponding PN code and a corresponding terminal ID when ordering multimedia data; And And a data reproducing process of decrypting the received encrypted data by using its own PN code and its own terminal ID. The method of claim 4, wherein the user registration and terminal ID assignment process is performed. Receiving user information from a user for receiving a multimedia service; Generating a PN code and a terminal ID not duplicated with another user based on the received user information; Storing the received user information, the generated PN code, and a terminal ID in a corresponding memory unit; and And transmitting the PN code and the terminal ID to a subscriber of the terminal assigned the terminal ID. The method of claim 4, wherein the data request and data encryption process is performed. Receiving user information of a user for receiving a multimedia service; Searching for a PN code and a terminal ID of the corresponding user based on the received user information; Encrypting data ordered by a client using the PN code; Encrypting the data using the retrieved terminal ID; And And transmitting the encrypted data to a corresponding subscriber. The method of claim 4, wherein the data reproduction process is Decrypting the encrypted data received from the multimedia service center using its PN code; Decrypting the data using its terminal ID; And And reproducing data restored to the original signal.